x86/speculation: Rework speculative_store_bypass_update()

The upcoming support for the virtual SPEC_CTRL MSR on AMD needs to reuse
speculative_store_bypass_update() to avoid code duplication. Add an
argument for supplying a thread info (TIF) value and create a wrapper
speculative_store_bypass_update_current() which is used at the existing
call site.

Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Reviewed-by: Borislav Petkov <bp@suse.de>
Reviewed-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>

3 files changed, 9 insertions, 4 deletions

diff --git a/arch/x86/include/asm/spec-ctrl.h b/arch/x86/include/asm/spec-ctrl.h
index 6e2874049afd..82b6c5a0d61e 100644
--- a/arch/x86/include/asm/spec-ctrl.h
+++ b/arch/x86/include/asm/spec-ctrl.h
@@ -42,6 +42,11 @@ extern void speculative_store_bypass_ht_init(void);
 static inline void speculative_store_bypass_ht_init(void) { }
 #endif
 
-extern void speculative_store_bypass_update(void);
+extern void speculative_store_bypass_update(unsigned long tif);
+
+static inline void speculative_store_bypass_update_current(void)
+{
+        speculative_store_bypass_update(current_thread_info()->flags);
+}
 
 #endif
diff --git a/arch/x86/kernel/cpu/bugs.c b/arch/x86/kernel/cpu/bugs.c
index 82422a04b506..f2f0c1b3bf50 100644
--- a/arch/x86/kernel/cpu/bugs.c
+++ b/arch/x86/kernel/cpu/bugs.c
@@ -598,7 +598,7 @@ static int ssb_prctl_set(struct task_struct *task, unsigned long ctrl)
          * mitigation until it is next scheduled.
          */
         if (task == current && update)
-                speculative_store_bypass_update();
+                speculative_store_bypass_update_current();
 
         return 0;
 }
diff --git a/arch/x86/kernel/process.c b/arch/x86/kernel/process.c
index 91c3398286d8..30ca2d1a9231 100644
--- a/arch/x86/kernel/process.c
+++ b/arch/x86/kernel/process.c
@@ -414,10 +414,10 @@ static __always_inline void __speculative_store_bypass_update(unsigned long tifn
                 intel_set_ssb_state(tifn);
 }
 
-void speculative_store_bypass_update(void)
+void speculative_store_bypass_update(unsigned long tif)
 {
         preempt_disable();
-        __speculative_store_bypass_update(current_thread_info()->flags);
+        __speculative_store_bypass_update(tif);
         preempt_enable();
 }